The purpose of this project is to define the mechanism of regulation of the globin genes in erythroid cells. Transcriptional regulation is being studied specifically by isolation of chromatin from various erythroid tissues of sheep and rabbit. The chromatin is transcribed in vitro with RNA polymerase, and synthesis of mRNA of sheep (beta for adult hemoglobin and gamma for fetal hemoglobin) are being prepared so that transcription of the individual genes may be studied. Techniques are also being developed to purify specific protein factors which may be important in transcriptional regulation.